Date: Wed, 15 Jan 1997 01:58:38 GMT
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Last-modified: Mon, 26 Feb 1996 19:04:04 GMT
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<TITLE> Robert Simon's Research Interests </TITLE>

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<H1> Robert Simon</H1>

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I am interested in multimedia, real-time, CSCW, network and distributed systems
research.  Below are some details of my work to date, if you're interested:


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<DT> Multimedia Communication Architecture

<DD> During my graduate
career, I have designed and implemented a multimedia communication
architecture for an Integrated Services Network.  DIPCS
(Distributed InterProcess Communication System) is distinguished by its use
of a new distributed process group model and its ability to allow a spectrum
of quality of service requirements to co-exist within a single call. DIPCS
provides guaranteed support for real-time multimedia traffic through a
general purpose admission control policy and a packet policing and service
policy. These policies support the end-to-end delay and synchronization
requirements of each connection. DIPCS provides a call model and connection
management system that is scalable to a Wide Area Network.

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<DT> Multimedia Routing Algorithms

<DD> Using the DIPCS call
specification and network architecture I have developed both centralized and
distributed multimedia routing algorithms. These algorithms are based on a
mathematical model of the network and of the real-time requirements of
multimedia traffic that predicts the probability of a route or set of routes
being able to support the traffic specification. These algorithms have two
parts. In the first part network performance is decomposed into a set of
independent link evaluation problems. A link blocks if it cannot support the
performance requirements of a new connection while maintaining support for
existing connections. My analysis allows the link blocking problem to be
determined by knowledge of only the traffic arrival rate and performance
requirements.

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<DD> The second part is a route assignment and optimization phase. I have
explored several methods for doing the optimization. The first is
similar to a classic steepest descent algorithm.  The second method is
by using an evolutionary computing technique.  My approach encodes the
problem as a tree. I define a set of genetic operators for mutation,
inversion and recombination. Based on the problem instance I use
domain-specific knowledge for initialization. Finally, I have
developed an optimization algorithm which can be implemented in
distributed or parallel fashion. This approach has produced quite
encouraging results for real-time multimedia routing. Simulation
results show that the blocking model coupled with an evolutionary
computing approach to routing assignment optimization is very
successful.

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<DT> Multimedia MedNet

<DD>  My research has found practical application
in Multimedia MedNet. MedNet's initial goal, the development
and implementation of a distributed real-time multimedia system for remote
monitoring of and collaboration during neurosurgery, has been achieved in
part through work that I began at Hewlett-Packard labs and continued at the
University of Pittsburgh. As the lead technical person I have produced a significant amount of software, including real-time
audio and call control programs that are part of the DIPCS system.

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